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    <script>
        let arr=[2, 6, 6, 1, 77, 52, 25, 7 ,7];
         //2. 数组的求和，平均数
         let he=0;
        let ping=0;
        for(let i=0;i<arr.length;i++){
             he=he+arr[i]
         }
         console.log(he);
         ping=he/arr.length
         console.log(ping);

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